Unwrap using Unique UV in XSI

Unique UV for unwrapping is the most easiest way to unwrap high polygon objects.

I am using a mid-res character head(775 quads) for this demonstration. This method can apply into all kinds of objects.

Import your model from any other software(.obj is the best format for pure model exportation).

Press "i" to get into edge component mode. At this stage what you want to do is to cut up the model into smaller pieces.

Select the edges to indicate where do you want to cut. Keep in mind that all you want is to avoid having a piece which has an over 60 degree angle of bending.

For selecting edges, hold shift for additional selection; shift+ctrl to deselect aditional. Once you are happy with your cutting, stay in edge component mode.

Mouse over your object and right click for pop up menu. Make sure that your pop up menu is "tagged edges". You'll get a different pop up if you are right clicking outside of your object or may not be getting any popup if you are not in component mode. Remember to press "i" if you got out of edge component mode by mistakes.

Select "disconnect components".

Your model will become something like this after disconnection.

The operation is under modeling stage. It will not effect your hireachy or any linked deformation. You can always freeze the object by clicking "Freeze M" on the lower right hand corner.

Unique UVs will place UV projections around the object base on whatever cropping angle you've assigned.

In Unique UV properties page set the angle as 90. Do not enable pre-smoothing. Leave everything as default and close the window.

Press 7 for texture editor or you may get it from a drop down menu under the top left hand corner of each view port. If you are already in texture editor before you pick the texture projection, you may have hit clear and reload in texture editor to show the UVs.

Now, you can see how Unique UV has splitted your UVs into multiple pieces arcording to how you've crop your object using disconnect edges.